Output DC voltage control system of a doubly salient-pole homopolar generator

A doubly salient-pole homopolar generator has been proposed as high efficiency and a wide speed range generator. This generator has salient-poles in stator cores similar to switched reluctance motors. Between two stator cores permanent magnets are inserted with magnetization to the thrust axis. The rotor structure of the doubly salient-pole homopolar generator is very similar to the one in the switched reluctance motors except that one rotor core is skew relative the other. Thus, the rotor has very simple structure and mechanical robustness. A control method of the doubly salient-pole homopolar machine with a square-waveform rectifier in generating region is proposed. First a feedback system realizing constant output DC voltage is constructed. With the proposed controller the doubly salient-pole homopolar machine is found to be operated at constant DC voltage with a wide speed range from 1000 r/min to 10000 r/min with the rated load. It is shown that the generator can be operated at the rated output power within rated terminal voltage and line current in the wide speed range.